Turbo compressor having a flow diversion channel

Abstract

In order to improve a turbo compressor comprising a compressor housing, in which an incoming gas volume flow is supplied to an impeller channel through an inlet channel, is compressed in the impeller channel by an impeller and is discharged from the impeller channel via an outlet channel, and a flow diversion channel which is provided in the compressor housing, extends outside of the impeller channel and the inlet channel, opens into the inlet channel with an opening on the inlet side and into the impeller channel with an opening on the impeller side and conveys a diversion volume flow between the openings as a function of a difference in pressure, in such a manner that it can be operated optimally with volume flows which are far below the volume flow provided for the design point it is suggested that the flow diversion channel have a cross-sectional flow area increasing in size up to the opening on the inlet side proceeding from the opening on the impeller side.

The invention claimed is: 
     
       1. Turbo compressor comprising a compressor housing, an incoming gas volume flow being supplied in said housing to an impeller channel through an inlet channel, being compressed in the impeller channel by an impeller and being discharged from the impeller channel via an outlet channel, and a flow diversion channel provided in the compressor housing and extending outside of the impeller channel and the inlet channel, said flow diversion channel opening into the inlet channel with an opening on the inlet side and into the impeller channel with an opening on the impeller side and conveying a diversion volume flow between the openings as a function of a difference in pressure, the flow diversion channel having a cross-sectional flow area increasing in size up to the opening on the inlet side proceeding from the opening on the impeller side, the flow diversion channel being adapted to be closed by a closure unit, said closure unit comprising a spring-loaded valve element. 
     
     
       2. Turbo compressor as defined in  claim 1 , wherein the cross-sectional flow area of the flow diversion channel increases constantly in size with increasing extension thereof from the opening on the impeller side towards the opening on the inlet side. 
     
     
       3. Turbo compressor as defined in  claim 1 , wherein a cross-sectional flow area of the opening on the inlet side is in the range of between 2.5 times and 3 times the cross-sectional flow area of the opening on the impeller side. 
     
     
       4. Turbo compressor as defined in  claim 1  wherein the flow diversion channel is formed by channel segments arranged next to one another in a circumferential direction with respect to an impeller axis, the channel segments being separated from one another in the circumferential direction. 
     
     
       5. Turbo compressor as defined in  claim 4 , wherein the channel segments are separated from one another by ribs extending in radial planes relative to the impeller axis. 
     
     
       6. Turbo compressor as defined in  claim 1 , wherein the opening of the flow diversion channel on the impeller side is located in an area of the impeller channel, the impeller having blades moving in said area. 
     
     
       7. Turbo compressor as defined in  claim 1  wherein the opening of the flow diversion channel on the impeller side is located in the region between ends of long impeller blades on the inlet side and ends of short impeller blades on the inlet side. 
     
     
       8. Turbo compressor as defined in  claim 1 , wherein the opening of the flow diversion channel on the impeller side is located in a surface extending constantly in relation to a flow guiding surface located upstream of this opening and a flow guiding surface located downstream of this opening. 
     
     
       9. Turbo compressor as defined in  claim 1 , wherein the opening of the flow diversion channel on the impeller side is designed to extend around the impeller axis in a circumferential direction. 
     
     
       10. Turbo compressor as defined in  claim 1 , wherein the opening of the flow diversion channel on the inlet side is located upstream of the impeller. 
     
     
       11. Turbo compressor as defined in  claim 10 , wherein the opening of the flow diversion channel on the inlet side is arranged at a distance from impeller blades corresponding at least to an extension of the impeller blades in the direction of the impeller axis. 
     
     
       12. Turbo compressor as defined in  claim 1 , wherein the opening of the flow diversion channel on the inlet side is located in a surface extending essentially parallel to a direction of flow of the gas volume flow in the inlet channel. 
     
     
       13. Turbo compressor as defined in  claim 12 , wherein the opening of the flow diversion channel on the inlet side is located in a surface extending constantly in relation to flow guiding surfaces in the inlet channel upstream of the opening and flow guiding surfaces downstream of the opening. 
     
     
       14. Turbo compressor as defined in  claim 1 , wherein the opening of the flow diversion channel on the inlet side is designed to extend circumferentially in relation to an impeller axis. 
     
     
       15. Turbo compressor as defined in  claim 1 , wherein the flow diversion channel deflects a diversion volume flow coming from the opening on the impeller side in the region of the opening on the inlet side to such an extent that it exits into the inlet channel with a direction of flow transverse to the direction of flow of the incoming gas volume flow. 
     
     
       16. Turbo compressor as defined in  claim 1 , wherein the flow diversion channel is adapted such that it facilitates a diversion volume flow from the opening on the impeller side to the opening on the inlet side during partial load operation. 
     
     
       17. Turbo compressor as defined in  claim 16 , wherein the flow diversion channel is designed such that it is in a position during partial load operation to convey more than 20% of the gas volume flow flowing to the impeller. 
     
     
       18. Turbo compressor as defined in  claim 1  wherein the flow diversion channel allows a partial load operation of the turbo compressor with gas volume flows between 40% of the gas volume flow provided in the design point and the gas volume flow in the design point. 
     
     
       19. Turbo compressor as defined in  claim 1 , wherein the closure unit comprises a flutter valve. 
     
     
       20. Turbo compressor as defined in  claim 1 , wherein the closure unit is configured to interrupt the diversion volume flow from the opening on the inlet side to the opening on the impeller side during an overload state. 
     
     
       21. Turbo compressor as defined in  claim 1 , wherein the closure unit is configured to suppress the diversion volume flow from the opening on the inlet side to the opening on the impeller side during partial load operation.